Battery coil construction having a ruffled edge electrode

ABSTRACT

AN IMPROVED CELL CONSTRUCTION IS UTILIZED IN WHICH A RUFFLED EDGE OF THE NEGATIVE PLATE EXTENS LONGITUDINALLY BEYOND THE EDGE OF THE POSITIVE PLATE AT ONE END OF THE BATTERY COIL AND A RUFFLED EDGE OF THE POSITIVE PLATE EXTENDS LONGITUDINALLY BEYOND THE EDGE OF THE NEGATIVE PLATE AT THE OPPOSITE END OF THE BATTERY COIL. TERMINAL STRAPS ARE ATTACHED TO THE EXTENDING RUFFLED EDGES OF THE RESPECTIVE PLATES.

G. P. CROMER Oct. 3, 1972 BATTERY COIL CONSTRUCTION HAVING A RUFFLED EDGE ELECTRODE Filed Oct. 7, 1970 FIG.|.

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II III II I ll II I II II INVENTOR GEORGE PHILLIP CROME HIS ATTORNEY.

United States Patent US. Cl. 136-13 4 Claims ABSTRACT OF THE DISCLOSURE An improved cell construction is utilized in which a rufiled edge of the negative plate extends longitudinally beyond the edge of the positive plate at one end of the battery coil and a rufiled edge of the positive plate extends longitudinally beyond the edge of the negative plate at the opposite end of the battery coil. Terminal straps are attached to the extending rufiied edges of the respective plates.

BACKGROUND OF THE INVENTION This invention relates to the construction of an electrochemical cell and more particularly to the type of cell construction in which a negative plate and a positive plate are wound with appropriate separators into a coil.

In Sugalski US. Patent No. 3,503,806 issued Mar. 31, 1970 and assigned to the assignee of this invention there is described and a claimed a construction of a battery coil in which one edge of the negative plate longitudinally extends beyond the positive plate at one end of the coil and one edge of the positive plate extends beyond the negative plate at the opposite end of the coil. This type of construction permits ease of construction of the battery coil including the attachment of terminal strips across the exposed edges of the respective plates by a plurality of welds to improve the ohmic connection between the plate and the terminal strap. The plates used in such coils comprise a fairly thin metal substrate upon which the active battery is deposited which, of course, results in an overall increase in the plate thickness. A small portion of the edge to be ultimately exposed is, however, kept free of the active material, among other reasons, to assure a good weld of the plate to the terminal strap. This, however, results in a thin exposed edge which may be bent during construction, cause injury to assemblers due to its thin edge, and in some instances, create misalignment problems during the winding process.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide an improved battery coil construction. Other objects of the invention will be apparent from the description and the drawings.

In accordance with the invention and in a specific embodiment thereof an improved battery coil construction is provided comprising a positive plate having one edge thereof ruffled, a negative plate having one edge ruffled, and separator means therebetween. The plates and the separator means are wound into a battery coil with the two plates longitudinally offset from one another so that the milled edge of one plate extends beyond the flat edge of the second plate at one end of the coil while the ruffled edge of the second plate extends beyond the flat edge of the first plate at the opposite end of the coil.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially-cutaway isometric view of the invention.

FIG. 2 is an end view of the invention.

FIG. 3 is a partially-cutaway view of a portion of the construction illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and particularly to FIG. 1, a battery coil constructed in accordance with the invention is generally illustrated at 2 comprising a positive plate 10, a first separator 16, a negative plate 20, and a second separator 26.

Plates 10 and 20, with separators 16 and 26 therebetween, are spirally wound to form coil 2. Plates 10 and 20 are longitudinally offset from one another, as well as from separators 16 and 26, to provide an extending edge 12 at one end of coil 2 comprising a continuous exposed edge of plate 10 and an extending edge 22 at the opposite end of coil 2 comprising a continuous exposed edge of plate 20.

In accordance with the invention, edges 12 and 22 respectively of plates 10 and 20 are formed with a rufiled or non-linear configuration as best seen in FIGS. 1 and 3. This configuration is used to impart strength to the otherwise thin exposed edge which, in the prior art construction, could be easily bent making subsequent attachment of the terminal strap diflicult. The construction also provides, as best seen in FIG. 2, a larger crosssection of the exposed edge available for welding to terminal strip 30. Terminal strip 30 may comprise, for example, two leg portions 32 and 34. Ruifled edge 12 is shown in dotted outline form beneath the leg portions so that the increased cross-sectional area of ruflled edge 12 beneath portions 32 and 34 may be more easily visualized. A raised central portion 36 is subsequently attached to the appropriate positive or negative terminal of the battery as the case may be. The attachment of the terminal straps to the terminals leading to the outside of the battery case form no part of the present invention and are therefore not shown. Attachment of the terminal straps to appropriate terminals carried in a battery casing is illustrated in the previously mentioned Sugalski patent, US. Patent No. 3,503,806 cross-reference to which is hereby made.

While the exact configuration of the ruffled edge may be varied somewhat, for example, the ruffles may be of a corrugated or undulating shape or they may be V-shaped or U-shaped. The overall width of the rufile preferably should not be greater than the width or thickness of the portion of the plate containing the active material. For example, in a specific embodiment wherein the plate thickness of the portion of the plate containing the active material was about 20-27 mils thick, the rufiled edge (which contains no active material) was about 17-18 mils wide from peak to peak. In this manner, the overall thickness of the plate and the resulting battery coil is not increased. It should be noted here that, in contrast, the plate thickness at the rufiied edge containing no active material is only about 2 mils thick before it is ruflied. Hence the reference to this edge in the prior art construction as a knife-edge.

The rufiied edge on the plate may be formed by placing the plate in a press containing appropriate dies or it may be formed by passing the plate through a pair of rollers having appropriately shaped knurled portions at the point of engagement of the edge portion of this plate containing no active material.

The resulting rufiled edge construction of the battery coil provides added strength to the exposed edge portions of the coil; provides an edge on the plate which is safer for an operator to handle in as much as the thin edge of the plate no longer represents a knife-edge; and the ruffled edge also provides a larger cross-sectional area capable of welding to a terminal strap of given area thus providing more ohmic contact between the plate and the terminal strap to reduce the resistance of the battery at this point. In addition, the construction of the invention provides another benefit in the rolling assembly of the battery coil. In the previous construction, using a thin straight edge on one side of each plate, a plate would occasionally become skewed during the winding process due to the thin edge slipping under the alignment guides which guide the sides of each plate during the rolling operation to insure the desired longitudinally offset of the positive and negative plates with respect to each other and to the separators therebetween. Using the rufiied plates of the invention proper alignment of the plates during the coiling operation is assured due to the effective increase in thickness of the edge of the plate having no active material adhering thereto.

What I claim as new and desire to secure by Letter Patent of the United States is:

1. An improved battery coil construction comprising a positive plate having a non-rufiled main portion containing active material and a ruffled end edge portion relatively free of active material, a negative plate having a non-ruflied main portion containing active material and a ruffled end edge portion relatively free of active material, and separator means therebetween, said plates and said separator means being wound together to form a coil, said plates being longitudinally ofiset from each other so that the ruffied edge of one plate extends beyond a flat edge of said other plate defining a continuous exposed ruflled edge of said one plate at one end of said coil, said ruffled edge of said other plate extending beyond a fiat edge of said one plate to define a continuous exposed 4 ruflied edge of said other plate on the opposite end of said coil.

2. The battery coil construction of claim 1 wherein a first terminal strap member is welded to said rulfied edges of said one plate by a plurality of welds and a second terminal strap member is welded to said ruflied edges of said other plate by a plurality of welds.

3. The battery coil construction of claim 1 wherein the overall Width from peak to peak of the ruflled portion of each plate is not greater than the thickness of the nonruflied main portion of each plate containing active material.

4. The battery coil construction of claim 3 wherein the thickness of the main portion of the plate containing active material is about 20-27 mils, the edge portion free of active material is about 2 mils thick, and the rufiiing of the edge portion increases the thickness of the edge to a peak to peak thickness less than the thickness of the main portion to maintain the overall thickness of the battery coil.

' References Cited UNITED STATES PATENTS 3,503,860 3/1970 Sugalski 13613 2,422,046 6/1947 Ruben 13610*7 2,487,499 11/1949 Webb 136l3 3,472,696 10/1969 Shoeld 136-13 ANTHONY SKAPARS, Primary Examiner U.S. Cl. X.R. 136-69, 134 

